diff --git a/sys/sys/mbuf.h b/sys/sys/mbuf.h
index 54525707d2ed..d7924807bcfe 100644
--- a/sys/sys/mbuf.h
+++ b/sys/sys/mbuf.h
@@ -31,7 +31,7 @@
  * SUCH DAMAGE.
  *
  *	@(#)mbuf.h	8.5 (Berkeley) 2/19/95
- * $Id: mbuf.h,v 1.16 1996/05/10 19:28:53 wollman Exp $
+ * $Id: mbuf.h,v 1.17 1996/08/19 03:32:10 julian Exp $
  */
 
 #ifndef _SYS_MBUF_H_
@@ -122,13 +122,14 @@ struct mbuf {
 #define	M_EXT		0x0001	/* has associated external storage */
 #define	M_PKTHDR	0x0002	/* start of record */
 #define	M_EOR		0x0004	/* end of record */
+#define	M_PROTO1	0x0008	/* protocol-specific */
 
 /* mbuf pkthdr flags, also in m_flags */
 #define	M_BCAST		0x0100	/* send/received as link-level broadcast */
 #define	M_MCAST		0x0200	/* send/received as link-level multicast */
 
 /* flags copied when copying m_pkthdr */
-#define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_BCAST|M_MCAST)
+#define	M_COPYFLAGS	(M_PKTHDR|M_EOR|M_PROTO1|M_BCAST|M_MCAST)
 
 /* mbuf types */
 #define	MT_FREE		0	/* should be on free list */